The field of the present invention is surgical methods for replacing and regenerating lost dermal collagen.
Disfiguring cutaneous irregularities, such as acne scars, wrinkles, and post traumatic depressions are a consequence of the loss of collagen that supplies the tissue thickness and maintains an even surface contour. Materials that have been used clinically to replace the lost tissue volume by subcutaneous injection include liquid silicone, fat, paraffin, liquid bovine collagen, and other fibrin compounds. Collagen suspensions, such as the liquid bovine collagen disclosed in U.S. Pat. Nos. 4,424,208, 4,582,640, and 4,642,117 are problematic in that they routinely fail to add endogenous collagen to tissue. Over time, the liquid disperses between cells allowing intercellular collagenase to digest the collagen substrate. Fat transferred from other areas is lumpy and has an unpredictable pattern of reabsorption. More resilient materials like silicone are gradually excreted into neighboring tissues from the depressed areas as the scar tightens again. Substances like paraffin can initiate an inflammatory response that causes further collagen loss. These filling techniques, in which liquid materials are injected through a needle into the scar, are disadvantageous because an injectable substance does not create a space between the layers of tissue in the recipient scar bed and therefore does not initiate new collagen deposition.
While laser treatments, dermabrasion and chemical peeling may stimulate the ingrowth of collagen from neighboring areas, they are seriously disadvantageous in that the nadir of the deepest scars and wrinkles cannot be safely treated, and hence the most noticeable defects remain unaffected. As a last resort when other techniques fail, the skin deformity may be completely excised and either sutured primarily or filled with punch grafts from neighboring areas. These techniques pose several risks including pigment changes, increased scarring, and persistent irregularities.
In fact, none of the above-described techniques affect the underlying problem which is the depletion of the collagen matrix that provides a natural support for epidermal growth. Unless fresh collagen is generated within the depression, the restored topography has dubious longevity.